nosql

I'm learning traditional Relational Databases (with PostgreSQL) and doing some research I've come across some new types of databases. CouchDB, Drizzle, and Scalaris to name a few, what is going to be the next database technologies to deal with?
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I need to do transactions (begin, commit or rollback), locks (select for update).
How can I do it in a document model db?
Edit:
The case is this:
I want to run an auctions site.
And I think how to direct purchase as well.
In a direct purchase I have to decrement the quantity field in the item record, but only if the quantity is great...

I've been trying to see if I can accomplish some requirements with a document based database, in this case CouchDB. Two generic requirements:
CRUD of entities with some fields which have unique index on it
ecommerce web app like eBay (better description here).
And I'm begining to think that a Document-based database isn't the be...

I've been hearing things about NoSQL and that it may eventually become the replacement for SQL DB storage methods due to the fact that DB interaction is often a bottle neck for speed on the web.
So I just have a few questions:
What exactly is it?
How does it work?
Why would it be better than using a SQL Database? And how much better i...

Hi Guys,
I have been stumbled on things like RDBMS alternatives very often now a days... And i am following some of the open source implementation..
wat i understaing is, its best suited for the web apps in large scale (like google & amazon).. they mainly concentrated on very large distributed data stores..
how this could help small ...

I've recently written a web app that uses couchdb. I like couchdb and it suited the app - which has a lot of dynamic behaviour and simply pulls JSON directly from couchdb. Being able to upload images via a browser is nice and it's a snap to do tweaks to document data. The replication also has made deployment a breeze as the app is a couc...

in this post Stack Overflow Architecture i read about something called nosql, i didn't understand what it means, and i tried to search on google but seams that i can't get exactly whats it.
Can anyone explain what nosql means in simple words?
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I'm wondering if some other non-relational database would be a good fit for activity streams - sort of like what you see on Facebook, Flickr (http://www.flickr.com/activity), etc. Right now, I'm using MySQL but it's pretty taxing (I have tens of millions of activity records) and since they are basically read-only once written and always ...

Given the following HBase schema scenario (from the official FAQ)...
How would you design an Hbase table
for many-to-many association between
two entities, for example Student and
Course?
I would define two tables:
Student: student id student data
(name, address, ...) courses (use
course ids as column qualifiers h...

And what are the pitfalls to avoid? Are there any deal breaks for you? E.g., I've heard that exporting/importing the Cassandra data is very difficult, making me wonder if that's going to hinder syncing production data to development environment.
BTW, it's very hard to find good tutorials on Cassandra, the only one I have http://arin.me/...

This question is partially related to an older question (Any CMS is Google App Engine compatible?) , but is slightly more general. It seems that in most CMS systems, the most fragile failure point is the database. Traditional database implementations scale poorly and will never be able to handle unforeseen spikes of traffic. Since Goo...

Lots of "BAW"s (big ass-websites) are using data storage and retrieval techniques that rely on huge tables with indexes, and using queries that won't/can't use JOINs in their queries (BigTable, HQL, etc) to deal with scalability and sharding databases. How does that work when you have lots and lots of data that is very related?
I can on...

Are there any document databases and/or key-value stores (something like Project Voldemort, MongoDB, etc.) that work well with .Net projects? Most of the options I've looked at so far seem to be more geared towards the non-Microsoft/Java/open-source technologies and I was wondering if anyone had any experience/recommendations with such ...

I can see myself using Project Voldermort to cache results from a Traditional RDBMS query. But in this case, it provides almost no major advantage over other (Java) caching system such as EHcache Jcache etc.
Where else could I use Project Voldermort or similar Key Value stores ? How are you using this in your business applications ?
...

Hi,
I would like to use some kind of nosql database in my web application which is written in asp.net mvc , but cannot find anything useful. I have a looked at MongoDB and CouchDB but i'd like to have better api (strongly typed not magic strings) for my queries than they have.
Is anything like this exists for .NET ?
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I must be missing something, because everything I've seen so far suggests that it isn't any more interesting than a single table for storing blobs and a second table for tags that apply to it.
Now I certainly can see some benefit to that from a design pattern, but why would I want to use a "document-oriented DBMS" instead of just buildi...

IIRC, each Facebook user can have 5000 friends. The average is 130, but the maximum is much higher. Each of those friends can have 'liked' zero or more entities drawn from a set of millions. When e.g. looking at a subset of those entities, grouped by N axes (e.g. by category and size), how would you find those that friends have liked?
W...